The invention relates to a diagnostic installation for producing tomographic images, comprising a support table for a patient, a plurality of x-ray or similar radiation-sources on one side of the support table, arranged in series or in an area array, for the production of a beam of rays, penetrating the patient lying on the support table, and an image detection installation on the other side of the support table, and comprising means for the step-by-step actuation of the radiation sources in any desired sequence, as well as for the purpose of moving the beam of rays and the image field of the image detection installation in mutually opposite directions, so that sharply defined images are formed of only those details disposed in a specified longitudinal layer of the body which is determined by the effective rotational axis of the beam of rays.
X-ray diagnostic installations are known wherein, at the one end of a guide bar, and above the support table, an x-ray tube is mounted, and, at the other end and below the support table, a cassette carrier for a film cassette is mounted. In order to change the direction of the beam of rays, the guide rod can be pivoted about a horizontal axis. In order to provide laminograms, the x-ray tube and the cassette carrier are moved in mutually opposite directions about the pivot axis. As a consequence, sharp images are formed on the film of only details of the particular body layer which is traversed by the pivot axis. Image-formation of all remaining details is more or less strongly blurred. In order to change the laminographic height, the pivot axis can be correspondingly adjusted at the guide bar.
Since the x-ray tube and the cassette carrier are moved in the case of these diagnostic installations, the times required for the preparation of laminographic images are comparatively long.
It has also been proposed (for example in German patent application P 26 47 167 corresponding to U.S. application Ser. No. 837,198 now abandoned), to provide as the radiation source a plurality of x-ray tubes arranged in a surface array, which are actuated in succession in a randomly selectable sequence, and to move the film cassette synchronously with the sequential actuation of the individual tubes. In addition, in order to provide laminograms at a relatively low laminographic angle (zonography), it has been proposed (in German patent application P 27 12 320 corresponding to U.S. application Ser. No. 866,017 now U.S. Pat. No. 4,149,082) to provide, for the purpose of image detection, an x-ray image intensifier with a synchronous deflection device controlled by a control generator.
In the case of the above-cited diagnostic installations, the orientation of the beams of rays emanating from the individual radiation sources present difficulties; in particular the problem arises that the subject to be examined is to be penetrated by the beam of rays at every laminographic height, on the one hand; but the patient is not to be exposed to any unnecessary radiation, on the other hand. It is the object of the present invention to provide a solution to this problem.